Myosins are evolutionarily conserved motor proteins that carry out a myriad of cellular functions. Using quantitative proteomics (Kelley et al., bioRxiv 2017) and reverse genetics, we identified an auxin-regulated Class VIII myosin, ATM1, that is required for hypocotyl elongation (Olatunji & Kelley 2020) and root growth (Olatunji et al., bioRxiv 2022). ATM1 is a plasmodesmal protein that is required for sugar-dependent growth in both shoots and roots. We are currently investigating the molecular function of ATM1 using genetics, live-cell microscopy, and proteomic approaches.